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Electrical
NGHNEERING LABORATORYNational Institute of
Standards and Technology
Technology Administration
U.S. Department of
Commerce
ElectromagneticsDivisionNISTIR 6632
January 2005
Programs, Activities, and
Accomplishments
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The Electronics and ElectricalEngineering Laboratory
One of NIST’s seven Measurement and Standards Laborato-
ries, EEEL conducts research, provides measurement services,and helps set standards in support of: the fundamental electronic
technologies of semiconductors, magnetics, and superconduc-
tors; information and communications technologies, such as
fiber optics, photonics, microwaves, electronic displays, and
electronics manufacturing supply chain collaboration; forensics
and security measurement instrumentation; fundamental and
practical physical standards and measurement services for
electrical quantities; maintaining the quality and integrity of
electrical power systems; and the development of nanoscale
and microelectromechanical devices. EEEL provides support tolaw enforcement, corrections, and criminal justice agencies,
including homeland security.
EEEL consists of four programmatic divisions and two matrix-managed offices:
Semiconductor Electronics Division
Optoelectronics Division
Quantum Electrical Metrology Division
Electromagnetics Division
Office of Microelectronics Programs
Office of Law Enforcement Standards
This document describes the technical programs of the
Electromagnetics Division. Similar documents describing the
other Divisions and Offices are available. Contact NIST/
EEEL, 100 Bureau Drive, MS 8100, Gaithersburg, MD 20899-8100, Telephone: (301) 975-2220, On the Web:www.eeel.nist.gov
On the cover (clocbA’ise from upper left): Rob Owings and Seongshik Oh, Elizabeth Mirowski
(© 2004 Geoffrey Wheeler), John Ladbury, Bill Riddle, Doug Tamura, Ron Ginley.
Electronics and ElectricalEngineering Laboratory
ElectromagneticsDivisionPrograms, Activities, and
Accomplishments
NISTIR 6632
January 2005
U.S. DEPARTMENT OF COMMERCEDonald L. Evans, Secretary
Technology Administration
Phillip J. Bond, Under Secretary of Commerce for Technology
National Institute of Standards and Technology
Hratch G. Semerjian, Acting Director
I
Electromagnetics Division
National Institute of Standards and Technology
325 Broadway
Boulder, Colorado 80305-3328
Telephone: (303) 497-3131
Facsimile: (303)497-3122
On the Web: http://www.boulder.nist.gov/div818/
Any mention of commercial products is for information only; it does not imply recommen-dation or endorsement by the National Institute of Standards and Technology nor does it
imply that the products mentioned are necessarily the best available for the purpose.
Contents
Welcome iv
Introduction to Technical Programs 1
Electromagnetics Division Staff 3
Radio-Frequency Electronics Group
Fundamental Microwave Quantities: Power 6
Fundamental Microwave Quantities: Scattering Parameters and Impedance 9
Fundamental Microwave Quantities: Noise 1
1
New Directions in Microwave Electronics: Nonlinear Device Characterization 14
New Directions in Microwave Electronics: Metrology for Wireless Systems 17
New Directions in Microwave Electronics: High-Speed Microelectronics 20
New Directions in Microwave Electronics: Radio-Frequency Nanoelectronics 23
Electromagnetic Properties of Materials 27
Radio-Frequency Fields Group
Antennas and Antenna Systems: Antenna Theory and Applications 31
Antennas and Antenna Systems: Antenna Near-Field Measurements 34
Antennas and Antenna Systems: Metrology for Radar Cross Section Systems 36
Electromagnetic Compatibility: Reference Fields and Probes 38
Electromagnetic Compatibility: Complex Fields 41
Electromagnetic Compatibility: Time-Domain Fields 44
Magnetics Group
Magnetodynamics 46
Magnetic Thin Films and Devices 50
Spin Electronics 55
Magnetic Recording Measurements 59
Nanoprobe Imaging 63
Superconductor Electromagnetic Measurements 68
Standards for Superconductor Characterization 73
Appendix A: Calibration Services 78
Appendix B: Postdoctoral Research Associateships 79
Appendix C: Prefixes for the International System of Units (SI) 90
Appendix D: Units for Magnetic Properties 91
Appendix E: Symbols for the Chemical Elements 92
Electromagnetics Division iii
WelcomeThe Electromagnetics Division is a critical national resource for a wide range of customers.
U.S. industry is the primary customer both for the division’s measurement services and for
technical support on the test and measurement methodology necessary for research, product
development, manufacturing, and international trade. The division represents the U.S. in inter-
national measurement intercomparisons and standards development related to radio-frequency
and microwave technology, electromagnetic fields, and superconductors. The division also
provides measurement services and expert technical support to other agencies of the federal
government to support its programs in domestic and international commerce, national defense,
transportation and communication, public health and safety, and law enforcement.
The division is organized into three groups. The groups’ projects are led by senior technical
staff with the assistance of physicists, engineers, technicians, and research associates, as well
as graduate and undergraduate students.
The Radio-Frequency Electronics Group conducts theoretical and experimental research todevelop basic metrology, special measurement techniques, and measurement standards neces-
sary for advancing both conventional and microcircuit guided-wave technologies; for charac-
terizing active and passive devices and networks; and for providing measurement services for
power, noise, impedance, material properties, and other basic quantities.
The Radio-Frequency Fields Group conducts theoretical and experimental research neces-sary for the accurate measurement of free-space electromagnetic field quantities; for character-
ization of antennas, probes and antenna systems; for development of effective methods for
electromagnetic compatibility assessment; for measurement of radar cross section and radiated
noise; and for providing measurement services for essential parameters.
The Magnetics Group develops measurement technology for industries broadly concernedwith magnetic information storage and superconductor power, spanning the range from practi-
cal engineering to theoretical modeling. The group disseminates the results of its research
through publications in refereed journals, presentations at conferences and workshops, and
participation in standards organizations.
A separate Division program is forging new directions for the advancement of wireless tech-nology via the development of standards for a new generation of broadband wireless accessproducts.
We hope that this collection of information will help you in understanding the work of thedivision and in making use of the technical capabilities and services that we provide for indus-try, government, and academia. We invite you to visit our Web site, http://www.boulder.nist.gov/div818. This site will provide you with more information on our projects and measurement-
related software, and reprints of our publications. Thank you for your interest in the
Electromagnetics Division.
Dennis Friday, Chief, Electromagnetics Division
Michael Kelley, Leader, Radio-Frequency Electronics Group
Perry Wilson, Leader, Radio-Frequency Fields Group
Ron Goldfarb, Leader, Magnetics Group
iv Electronics and Electrical Engineering Laboratory
Introduction to Technical ProgramsThe division carries out a broad range of technical programs focused on the precise realization
and measurement of physical quantities throughout the radio spectrum. Key directions in-
clude: (a) the development of artifact reference standards, services and processes with which
industry can maintain internationally recognized measurement traceability; (b) the advance-
ment of technology through the development of new measurement techniques that are theo-retically and experimentally sound as well as relevant and practical; (c) the assessment of total
measurement uncertainties; and (d) the provision of expert technical support for national and
international standards activities. We strive to perform leading-edge, high-quality research inmetrology that is responsive to national needs. Division programs cover the following techni-
cal areas:
Fundamental Microwave Quantities
The fundamental microwave quantities program develops standards and methods for measur-
ing impedance, scattering parameters, attenuation, power, voltage, and thermal noise, and pro-
vides essential measurement services to the nation.
New Directions in Microwave ElectronicsNew thrusts in microwave metrology include the characterization of nonlinear properties ofdevices, the linear and nonlinear characterization of wireless systems, precise on-wafer mea-
surement of ultra-high-speed waveforms, and methods for contact and noncontact electrical
probing of nanoscale electronic structures.
Electromagnetic Properties of Materials
The electromagnetic properties of materials program develops theory and methods for mea-
suring the dielectric and magnetic properties of bulk and thin-film materials throughout the
radio spectrum.
Antennas and Antenna Systems
The antennas and antenna systems program develops theory and techniques for measuring the
gain, pattern, and polarization of advanced antennas; for measuring the gain and noise of large
antenna systems; and for analyzing radar cross-section measurement systems.
Electromagnetic Compatibility
The electromagnetic compatibility program develops theory and methods for measuring elec-
tromagnetic field quantities and for characterizing the emissions and susceptibility of elec-
tronic devices and systems, in both the frequency and time domains.
Magnetodynamics and Spin Electronics
The program in magnetodynamics and spin electronics undertakes experimental research on
fundamental aspects of magnetization switching, precession, and damping at the nanoscale for
applications in magnetic information storage (such as magnetoresistive read heads, recording
media, and magnetic random access memory) and magnetic devices (such as oscillators driven
by the transfer of quantum-mechanical electron spin angular momentum to magnetic films).
Magnetic Sensors and Scanned-Probe Microscopy
The program in magnetic sensors and scanned-probe microscopy is developing new sensors
and systems for the low-noise detection of extremely weak magnetic fields for imaging and
measurement applications in data storage, microelectronics, medicine, and national security.
Superconductor Characterization and Standards
The program in superconductor characterization and standards develops measurement methods for
the electric, magnetic, and mechanical properties of high-temperature and low-temperature super-
conductor wires and tapes for power applications.
Electronics and Electrical Engineering Laboratory
Electromagnetics Division Staff
Dennis Friday, Division Chief, (303)497-3 1 3
1
Cindy Kotary, Secretary, -3132
Linda Den; Administrative Officer, -4202
Roger Marks, -3037
Gerome Reeve, Research Associate, -3557
Kate Remley, -3652
Lindsey Vaughan, Student, -3880
Claude Weil, Research Associate, -5305
Radio-Frequency Electronics Group
Michael Kelley, Group Leader, (303) 497-4736
Susie Rivera, Secretary, -5755
Measurement Services
Puanani DeLara, -3753
Nonlinear Device Characterization
Don DeGroot, Project Leader, -7212
Jeffrey Jargon, -3596
Giovanni Loglio, Guest Researcher, -7212
Metrology for Wireless Systems
Kate Remley, Project Leader, -3652
Michael McKinley, -4645
Marc Rutschlin, Research Associate, -4674
High-Speed Microelectronics
Dylan Williams, Project Leader, -3138
Yungseon Eo, Research Associate, -4727
Eyal Gerecht, Research Associate, -4199
Dazhen Gu, Research Associate, -3939
Arek Lewandowski,
Research Associate, -4665
Juanita Morgan, -3015
Joshua Wepman, Student, -4583
Radio-Frequency Nanoelectronics
Pavel Kabos, -3997
Mitch Wallis, Research Associate, -5089
Simone Lee, Graduate Student -4143
Electromagnetic Properties of Materials
Jim Baker-Jarvis, Project Leader, -5621
Richard Geyer, -5852
Michael Janezic, -3656
Bill Riddle, -5752
Jim Booth, -7900
Kenneth Leong, Student, -4369
Susan Schima, -7213
Power Standards
Tom Crowley, Project Leader, -4133
Jeff Bridges, -3381
Fred Clague, Research Associate, -5778
George Free, -3609
James McLean, -4394
Network Analysis
Ron Ginley, Project Leader, -3634
John Grosvenor, -5533
John Juroshek, Research Associate, -5362
Denis LeGolvan, -3210
Ann Monke, -5249
Marilyn Packer, -523
1
Noise Standards
James Randa, Project Leader, -3150
Robert Billinger, -5737
Amanda Cox, Research Associate, -4653
David Walker, -5490
Justin Eiler, Student, -4698
Electromagnetics Division 3
Radio-Frequency Fields Group
Perry Wilson, Group Leader, (303) 497-3406
Ruth Marie Lyons, Secretary, -3321
Antenna Theory and Applications
Michael Francis, Project Leader, -5873
Lorant Muth, -3603
Ronald Wittmann, -3326
Antenna Near-Field Measurements
Katie MacReynolds, -3471
Jeffrey Guerrieri, -3863
Carl Stubenrauch, Research Associate, -3927
Doug Tamura, -3694
Reference Fields and Probes
Keith Masterson, Project Leader, -3756
Dennis Camell, -3214
David Novotny, -3 1 68
Complex Fields
Galen Koepke, Project Leader, -5766
David Hill, Research Associate, -3472
Christopher Holloway, -6184
John Ladbury, -5372
Ed Kuester, Research Associate, -4312
Alpesh Bhobe, Research Associate, -3142
William Young, Research Associate, -4649
Randal Direen, Research Associate, -5766
Time-Domain Fields
Robert Johnk, Project Leader, -3737
Chriss Grosvenor, -5958
Seturino Canales, -5702
Ben Davis, Research Associate, -7547
Magnetics Group
Ron Goldfarb, Group Leader, (303)497-3650
Ruth Corwin, Secretary, -5477
Kevin Landin, Student, -4406
Magnetic Recording Measurements
David Pappas, Project Leader, -3374
Fabio da Silva, Research Associate, -3873
Julie Frankel, Student, -4387
Sean Halloran, Graduate Student, -4651
Stephen Hill, Graduate Student, -4660
Robert Owings, Research Associate, -4692
Seongshik Oh, Research Associate, -4655
David Stevenson, Student, -4577
Shannon Willoughby,
Research Associate, -4725
Magnetodynamics
Tom Silva, Project Leader, -7826
Forrest Chamock, Research Associate, -4356
Thomas Gerrits, Research Associate, -466
1
Tony Kos, -5333
Jim McGuire, Research Associate, -4324
Mike Schneider, Research Associate, -4203
Nanoprobe Imaging
John Moreland, Project Leader, -3641
Eric Langlois, Research Associate, -4350
Li-Anne Liew, Research Associate, -4197
Shawn Liu, Student, -5847
Dong-Hoon Min, Research Associate, -4345
Elizabeth Mirowski, Research Associate,
-4458
Daniel Porpora, Student, -5477
Gary Zabow, Research Associate, -4657
Electronics and Electrical Engineering Laboratory
Magnetics Group (continued)
Magnetic Thin Films and Devices
Stephen Russek, Project Leader, -5097
Brant Cage, Research Associate, -4224
Stephen Downey, Graduate Student, -442
1
Shehzaad Kaka, Research Associate, -7365
Andrew McCallum, Graduate Student, -4282
Kevin Pettit, Research Associate, -4564
Matt Pufall, -5206
Bill Rippard, -3882
Nate Stutzke, Graduate Student, -4453
Standards for SuperconductorCharacterization
Loren Goodrich, Project Leader, -3143
Ted Stauffer, -3777
Superconductor ElectromagneticMeasurements
Jack Ekin, Project Leader, -5448
Mike Abrecht, Research Associate, -4496
Najib Cheggour, Research Associate, -3815
Cam Clickner, -5441
Electromagnetics Division 5
Fundamental Microwave Quantities:Power
Technical Contacts:
Tom CrowleyRon Ginley
Staff-Years (FY 2004):
3 professionals
3 technicians
Goals
This project develops, maintains, and improves
standards, systems, and methods for measuring
power over the frequency range from 1 00 kilohertz
to 1 1 0 gigahertz. It provides measurement services
and support to U.S. industrial and government labo-
ratories.
Jim McLean prepares to lower a waveguide micro-wave calorimeter into a water bath. © GeoffreyWheeler
Customer Needs
A system’s output power level is frequently the crit-ical factor in the design, and ultimately the perfor-
mance, of radio-frequency (RF) and microwave
equipment. Accurate measurements of power and
voltage allow designers and users ofmeasuring and
test equipment to determine whether performance
specifications are met. Inaccurate measurements
can lead to over-design of products, and hence, in-
creased costs. Economic gains are realized through
improvements in accuracy. State-of-the-art calibra-
tion services are needed so that customers can main-
tain quality assurance programs in the manufacture
and distribution of their products. The availability
of these services allows customers to be globally
competitive.
Several emerging technologies have microwave
power metrology needs that will require new ser-
vices. High-bit-rate optoelectronics devices such
as those used for the internet will need broadband
characterization up to 1 1 0 gigahertz. An increas-ing number of applications, including some in
homeland security, are using frequencies above 100
gigahertz.
Technical Strategy
The two primary areas of current work in micro-
wave power are improvements in measurements
above 50 gigahertz and maintenance ofcalibration
services with a wide variety of connector types.
Basic research into quantum-based microwave
power measurement is also being performed.
Measurements above 50 Gigahertz— For a num-ber of years, power measurements at NIST above
50 gigahertz have been based on calorimetric and
six-port measurements. NIST’s internal standards
were characterized in the calorimeters and the mea-
surements transferred to customer devices by use
of a six-port. The internal standards were modified
commercial power sensors, and the calorimeters
were designed specifically for these standards.
Measurement services have been available in 1 gi-
gahertz steps from 50 to 75 gigahertz and from
92 to 96 gigahertz. It takes about 1 day to charac-
terize a few customer devices at each frequency.
Improvements in our standards are needed for a
number of reasons. Frequency coverage in 1 giga-
hertz steps is not adequate for characterizing broad-
band devices such as optoelectronics devices that
operate at 40 gigabits per second. It is also not ad-
equate to cover new applications at frequencies
above 75 gigahertz. The commercial power sen-
sors that were originally modified to create our in-
ternal standards can no longer be obtained. Exist-
ing internal standards no longer produce reliable
results in the calorimeters.
In order to address these problems, power mea-
surement services between 50 and 110 gigahertz
are being rebuilt with numerous improvements. For
some applications, manually tuned Gunn diode
oscillators have been replaced with backward-wave
oscillators that can be electronically controlled. It
is therefore, much easier to do multiple frequency
measurements. A single backward-wave oscillatortube can also cover the entire frequency band from
75 to 110 gigahertz. A direct comparison systemthat can evaluate a customer device at about
50 frequencies per day will replace the six-port
6 Electronics and Electrical Engineering Laboratory
systems. The WR-15 (50 to 75 gigahertz) systemhas been completely evaluated, while the WR-10(75 to 1 1 0 gigahertz) system has been constructed,
but not yet evaluated. New calorimeters have beendesigned for both WR-10 and WR-15. They willaccommodate a wider variety of internal standards
than the present calorimeters. They were also de-
signed so that a feedback system could be imple-
mented and reduce the time required per frequency.
Future plans include the extension of the direct
comparison measurements to 1.85 millimeter co-
axial connectors that will allow measurements from
DC to 65 gigahertz with a single connector. Finally,a long-term goal is to develop a new internal stan-dard to replace our existing standards.
The immediate beneficiary of these improvements
will be the Optoelectronics Division. It has primary
responsibility for characterizing high-bit-rate digi-
tal systems that are currently being developed for
optical-fiber communications systems and the
internet. In order to do that, they have an immedi-
ate need for broadband RF power calibration ofdiode detectors from DC to 65 gigahertz (prefer-ably in 100 megahertz steps) with an eventual re-
quirement of measurements up to 1 10 gigahertz.
John Jnroshek measuring a coaxial power detector.
© Geoffrey Wheeler
Other customers will also benefit from these im-
provements. The transition from six-port to direct
comparison measurements will result in a lower cost
service with comparable uncertainty. Generally,
coaxial systems are more useful to most customers
than waveguide systems. Thus, the addition of a
1 .85 millimeter coaxial connector direct compari-
son system will significantly help industry develop
new products with these connectors. For the near
future, 1 .85 millimeter devices will be traceable to
the WR-15 and 2.4 millimeter calorimetric primarystandards.
We plan to assemble, test, and evaluate uncertaintyof new WR-15 and WR-10 calorimeters. We willdevelop a feedback system for the new calorim-
eters that reduces the period of time in which the
RF source must deliver power. This is importantfor extending the lifetime of the backward wave
oscillator tubes. We will complete a direct com-parison system for power detectors with 1 .85 mil-
limeter coaxial connectors.
Maintenance and Improvement of ExistingStandards— We offer RF and microwave powermeasurement services for 5 types of coaxial con-
nectors and 7 waveguide sizes. Short-term mainte-
nance of these systems requires that they be con-
tinuously checked for reliability and updated as
needed. The quality system defines the checks and
measurements that need to be done.
We also offer voltage measurements from 30 kilo-hertz to 1 00 megahertz and a high-power ( 1 to 1 000
watt) measurement service from 1 to 1000 mega-
hertz. On a long-range time scale, measurementsystem components need to be replaced in order to
maintain the quality of the system. Of particularconcern in this area is that the bolometric standards
with WR-15, WR-10, and 2.4 millimeter coaxial
connectors cannot be replaced. We anticipate thatwe will have to develop our own standards in the
future.
In the near future, we will deliver calibration ser-vices in power and voltage, update the quality
manual, offer high power measurements at both the
input and output plane of the customer’s DUT, and
transfer 100 kilohertz to 10 megahertz measure-
ments to a direct-comparison system.
Quantum Based RF Power Measurement— RFpower measurements have traditionally been trace-
able to DC power measurements. NIST’s primaryand transfer standards all rely on this technique in
which temperature changes due to RF and DCpower are measured and compared. The largest
uncertainty in the measurements is due to differ-
ences in the location of the RF and DC power dis-sipation.
An alternative approach is to measure the field
strength of microwaves through their effect on the
quantum state of atoms. In this measurement, a
group of atoms are prepared in a single quantum
state. They are then exposed to microwaves at a
frequency that corresponds to the energy difference
between this state and a second quantum state. The
atoms will oscillate between the two states at a fre-
quency that is proportional to the field strength.
The process is known as a Rabi oscillation. By
measuring the number of atoms in each state, the
field strength can be determined. A proof-of-con-cept experiment was conducted in collaboration
with the Physics Laboratory. The next stage in this
work will be an experiment that accurately com-
pares a traditional measurement with the quantum
measurement.
Accomplishments
Quantum-Based Microwave Power — Incollaboration with the Physics Laboratory, the RFmagnetic field strength of 9. 193 gigahertz micro-
waves in a cavity was determined by measuring
the Rabi oscillation of cesium atoms passing
through the cavity. The experiment used a small
fountain apparatus originally designed for use as
an atomic clock. The magnetic field measurement
depends only on atomic parameters and the time
the atoms spent in the cavity. This ties an RF mea-surement directly to atomic parameters. Additional
measurements of the cavity properties were used
to determine the microwave power incident on the
cavity. This was compared with the incident power
as determined through a traditional measurement.
The two differed by 5 percent, which was consider-
ably smaller than the uncertainty in the comparison.
Waveguide Direct Comparison— A direct-comparison system for WR-15 and WR-10waveguide has been constructed. The WR-15 sys-tem has been tested and its uncertainty analysis
completed. This system will reduce the time re-
quired to evaluate a customer mount by a factor of
about 50 from our previous six-port. It also has a
slightly lower uncertainty on average.
New Waveguide Calorimeters— New WR-15 and WR-10 calorimeters have been designed.These new calorimeters will replace older versions
that have become unreliable. They will be able to
characterize a wider variety ofbolometric standards
and have been designed so that feedback control
can be used to reduce the time required for source
operation. These improvements will make it easier
to calibrate instruments at a greater number of fre-
quencies and provide more options for transfer
measurements, and should also be compatible with
any future bolometric standards developed by
NIST.
Quality Manual—A quality system has beenimplemented for both calorimetric power measure-
ments and for the transfer of those measurements
to customer systems through six-port and direct
comparison systems. The quality system largely
documents measurement practices that have been
in place for a number of years.
Calibrations
Power and voltage calibrations were performed
on 128 devices in FY 2003 and on 129 devices inFY 2004.
Short Courses
Annual presentation at NIST/ARFTG ShortCourse on Microwave Measurements.
Collaborations
Physics Laboratory, quantum-based RF powermeasurement.
Recent Publications
T. P. Crowley, E. A. Donley, and T. P. Heavner, “Quantum-
Based Microwave Power Measurements: Proof-of-Concept
Experiment,” Rev. Sci. Instrum. 75, 2575-2580 (August 2004).
T. P. Crowley and F. R. Clague, “A 2.4 mm Coaxial PowerStandard at NIST." British Electromagnetic Conf., Harrogate,
U. K. (November 2001).
J. R. Juroshek, “NIST 0.05-50 GHz Direct Comparison PowerCalibration System,” Conf. Precision Electromagn. Meas.,
Sydney, Australia, pp. 166-167 (May 2000).
Electronics and Electrical Engineering Laboratory8
Fundamental Microwave Quantities:Scattering Parameters and Impedance
Goals
This project provides traceability for microwave
measurements in scattering parameters, impedance,
and attenuation. It supports the microwave indus-
try by developing standards and new measurementtechniques. It develops methods for assessing and
verifying the accuracy of vector network analyzers.
Customer Needs
Vector network analyzers (VNAs) are the single
most important instrument in the microwave indus-
try. These instruments are commonly found on pro-duction lines and in calibration and research labo-
ratories. Vector network analyzers are typically cali-
brated daily, and the accuracy oftheir measurements
can vary significantly after calibration, depending
on the operator’s skill, the quality of the calibra-
tion standards, and the condition of the test ports.
The microwave industry needs cost-effective tech-
niques to monitor and verify the accuracy ofVNAmeasurements. In addition, industry requires vali-
dation oftechniques and procedures they develop.
We support these needs by providing consultationson measurement techniques and uncertainty char-
acterization. We also offer an extensive array ofmeasurement services that allow VNA users to es-tablish and gain confidence in their own capabilities.
Technical Strategy
There is an increasing demand for scattering-pa-
rameter (^-parameter) measurements. This is par-
ticularly evident for measurements above 50 giga-
hertz. The demand is coming from many emerging
technologies including high-bit-rate digital systems
and other communication systems. Support for
higher frequencies and new connector types isneeded. At the same time, the demand for existing
measurement services is also increasing. We aredeveloping improved x-parameter calibration ser-
vices and techniques to support industry needs. The
principal areas of our efforts include: support for
existing calibration services; developing new cali-bration capabilities; and developing new calibra-tion and measurement technology and techniques.
The existing calibration services cover an enonnous
range of connector types and frequency ranges.
Both coaxial connector and waveguide devices are
measured. Even though the commercial VNAs havemeasurement capabilities and uncertainties simi-
lar to those that NIST has, there is still a very strong
NIST s-parameter andpower measurement services
demand for the classical artifact-based type ofmea-
surement to support the very large installed base of
legacy equipment. We support this demand withdevice-based measurement services. Additionally,
the existing x-parameter services are necessary to
support the mismatch correction for power calibra-
tions. Verification of measurement systems and
calibrations is one ofour most important tasks, and
we will continue to improve our check-standardcapabilities through an improved database and op-
erator interface.
International comparisons play an important part
in validating x-parameter measurements at NIST.
These comparisons help us ensure that our x-pa-
rameter capabilities are comparable to those of
other national metrology institutes. This relation-
ship insures that users of the NIST calibration ser-vices will be able to compete in the international
market. We will continue to participate in as manyinternational comparisons as is practical.
Another service we provide to help customers haveconfidence in their measurements is the NIST Mea-surement Comparison Program. This program al-
lows a customer to measure a set of devices previ-
ously characterized by NIST, and then compare
their results to NIST’s along with the identifica-
tion of NIST’s uncertainties. This program will be
broadened to include new connector types and ad-
ditional capabilities.
New services are being developed to address theincreased demand from the optical-fiber commu-
nication industry, wireless systems, and aerospace,
military and general communications industries, to
name a few. Higher frequencies and smaller con-
nector sizes are being used on a routine basis. We
Technical Contact:
Ron Ginley
Staff-Years (FY 2004)
2 professionals
4 technicians
Electromagnetics Division 9
are meeting some ofthese needs by adding the 1 .85
millimeter and the 1.0 millimeter connector size
capabilities to our measurement services in the next
year. We are also looking at support requirementsfor other connector types including the 7/16 con-
nector and 75-ohm-based connectors.
There is a general agreement among the principal
users and makers ofVNA systems that there is stillmuch to be understood aboutVNA calibrations andmeasurements. We are taking a very active role indeveloping VNA calibration and measurementtheory and techniques. We have developed thetheory and techniques for correcting lower accu-
racy Open-Short-Load calibrations to almost the
accuracy ofthe line-reflect-line (LRL) calibrations
(regarded as the most accurate) for one-port mea-
surements. We will be pursuing a similar correc-tion process for two-port measurements. Because
of the parity between customer capabilities and
those at NIST, we are looking at different ways tosupport VNA systems in industry. Verification ofVNA calibrations is very important; the currentverification process is not as good as it needs to
be. We have developed a program that will com-pare the contents on verification disks to measure-
ments made based on LRL calibrations, and thenwe will write new verification disks based on theLRL measurements and uncertainties. We currentlyhave the capability for only a few of the verifica-
tion disk formats; we will expand these capabili-ties and support new formats for VNA systems thatare just becoming available.
We will continue to provide 5-parameter measure-ments to industry, establish 1 .85 millimeter 5-pa-
rameter calibration service, establish 1 .85 millime-
ter and 1.0 millimeter NIST Measurement Com-parison Program Kits, provide software and tech-
niques to support the DOD’s use of commercialVNAs, add capabilities for the Agilent 8753 andPNA series VNAs to the verification disk program,finish development of the Web-based check stan-
dard database for 5-parameter and power measure-
ments, and investigate methods to enhance two-port
calibrations on VNAs.
Accomplishments
The 30 megahertz Precision Attenuation Mea-
surement System was transferred to the U.S. ArmyPrimary Standards Laboratory. The transferred sys-
tem replaced older equipment at the Army.
We delivered an updated System 3 Dual Six-Port System (18 to 40 gigahertz) to the Navy Pri-
mary Standards Laboratory. This system will help
Calibrating the WR-42 six-port system
support critical, high-frequency waveguide mea-
surements made by the Navy.
We developed and delivered a suite ofVNAsoftware to the Air Force Primary Standards Labo-
ratory. This software included programs to calibrate
commercial VNAs, take measurements from theVNAs, read and write corrected verification disks,read and compare calibration disk’s data, and one-
port calibration correction routines. The Air Force
estimates that the use of these packages will save
them in excess of $ 1 00 000 a year.
A quality system has been implemented for s-parameter measurements.
Calibrations
The 5-parameter and impedance measurement
services were performed on 124 devices in FY 2003and on 203 devices in FY 2004.
Short Courses
Annual presentation at NIST/ARFTG ShortCourse on Microwave Measurements
Collaborations
Optoelectronics Division, oscilloscope and power
head calibrations
Committee Participation
ARFTG Executive Committee; NCSLI Mea-surement Comparison Program Committee, NCSLI
Intrinsic and Derived Standards Committee, and
NCSLI U.S. National Measurement RequirementsCommittee.
Recent Publication
J. R. Juroshek, “Correcting for Systematic Errors in One-Port
Calibration Standards,” 62ndARFTG Conf. (December 2003).
Electronics and Electrical Engineering Laboratory10
Fundamental Microwave Quantities:Noise
Goals
This project develops methods for very accurate
measurements of thermal noise and provides sup-
port for such measurements in the communications
and electronics industries and in other government
agencies.
Amplifier noise-parameter measurements using two
cryogenic standards, one to calibrate the radiometer
and onefor input to the amplifier.
Customer Needs
Noise is a crucial consideration in designing or as-
sessing the performance of virtually any electronic
device or system that involves detection or pro-
cessing of a signal. This includes communications
systems, such as cellular phones and home enter-tainment systems, as well as systems with internal
signal detection and processing, such as guidance
and tracking systems or electronic test equipment.
The global market for microwave and millimeter-
wave devices in these areas is huge and will grow
larger. Important trends requiring support include
the utilization of higher frequencies, the growing
importance of low-noise amplifiers and transistors,
and the perpetual quest for faster, less expensive
measurements. The two most important noise-re-
lated technical parameters requested by industry
are the noise temperature of a one-port source and
the noise figure of an amplifier.
Noise power is also the quantity that is measured
in passive remote sensing, such as that used to
measure properties of the earth’s surface from sat-
ellites or airplanes. The growing importance ofsuch
measurements for climate monitoring, weather fore-
casting, agriculture, and other applications has high-
lighted the need for better calibration techniques,
smaller uncertainties, and compatibility between
results from different instruments.
Technical Strategy
We are working in three general areas: traditionalnoise-temperature measurements, characterization
of amplifier and transistor noise properties, and
calibration of remote-sensing radiometers. In tra-
ditional noise-temperature measurements, we of-fer measurement services at 30 and 60 megahertz
and from I to 40 gigahertz for coaxial sources, and
from 8.2 gigahertz to 65 gigahertz for waveguide
sources. Recent improvements have reduced the
time required for these measurements, thereby re-
ducing the costs to our customers.
The second general thrust of the project is in am-
plifier and transistor noise-parameter measure-
ments. The long-term goals in this area are to im-
prove techniques for measurement of noise param-
eters of low-noise amplifiers and transistors, to
develop measurement capability for noise param-
eters of amplifiers with coaxial connectors from 1
to 12 gigahertz, and to provide a mechanism for
industry to access this capability, either through
measurement comparisons or a measurement ser-
vice.
A new thrust of the project is in improving meth-ods for calibration and validation ofmicrowave ra-
diometers used for remote sensing from satellite or
airplane. The central element of this effort will be
the development ofmicrowave brightness-tempera-
ture standards, comprising both standard radiom-
eters and standard calibration targets. The standard
radiometers will be used to measure customer cali-
bration targets at NIST, and the standard calibra-
tion targets will be used in measurements at out-
side facilities, as well as for comparison measure-
ments with the NIST standard radiometer.
Our goals for this coming year are to measure the
noise parameters of a low-noise amplifier for an
interlaboratory comparison with NPL, measure the
noise parameters of a cryogenic amplifier belong-
ing to the Terahertz Project, and measure noise
parameters of ultra-large-scale integration (ULSI)
devices on wafer for comparison to IBM andRFMD. We intend to study the uncertainties in on-wafer measurements ofnoise parameters; design a
Technical Contact:
Jim Randa
Staff-Years (FY 2004):
2.5 professionals
1 .5 technicians
1 research associate
Electromagnetics Division 11
temperature-controlled, shielded, anechoic cham-
ber for standard radiometer(s); use the Physics
Laboratory’s infrared (IR) imaging system to study
thermal gradients in a calibration target used for
microwave remote sensing; and continue to pro-
vide noise-temperature measurement services.
Calibration target being tested in anechoic chamber.
Accomplishments
Amplifier Noise-Parameter Measurements
and Verification — The Noise Project completeddevelopment of a measurement capability for noise
parameters oflow-noise amplifiers (LNAs), includ-
ing a Monte Carlo assessment of uncertainties. Wealso completed and successfully implemented two
types of verification tests for such measurements.
All tests were satisfied within the uncertainties,
thereby providing support for both the measure-
ment results and the associated uncertainty esti-
mates.
Variable-Termination Unit—A variable-ter-mination unit (VTU) was designed, fabricated, and
tested. The VTU will be used in noise-parametermeasurements, allowing automated switching to an
array of different input terminations for the ampli-
fier, rather than the manual disconnecting and con-
necting that is currently used.
Traceability for Microwave Remote-Sens-
ing Measurements — A plan was developed forestablishing traceability to NIST for microwave
remote-sensing measurements. The plan includes
the theory necessary to link microwave remote-
sensing measurements to primary noise standards.
It was documented in a NIST internal report and in
a conference paper.
Measurement of Microwave Brightness
Temperature— Preliminary measurements wereperformed on a hot calibration target borrowed from
the NOAA Environmental Technology Laboratory.A standard gain horn (SGH) was characterized by
the Antenna Metrology Project and was connected
to the measurement plane of the Noise Project’s
WR-42 waveguide radiometer to form a standardradiometer for remote sensing. This standard radi-
ometer was then set up to view the calibration tar-
get mounted in the anechoic chamber. The target’s
brightness temperature was measured for different
distances and compared to the nominal brightness
temperature based on the sampled physical tem-
perature. Satisfactory to good agreement was ob-
tained, and possible areas of improvement were
identified.
Target Reflectivity — A study performed inFY 2004 on the effects of target reflectivity in thecalibration of microwave remote-sensing radiom-
eters was documented in a conference paper and a
journal paper. This study found that a common ap-proximation used in calibrating microwave radi-
ometers leads to errors that can be quite signifi-
cant.
Detector Linearity Study— Measurementswere made on tunnel diode detectors of the type
typically used in microwave remote-sensing radi-
ometers. These measurements included variations
in detector temperature as well as output load im-
pedance. Results point to improved test methods
and a way to greatly reduce the cost associated with
radiometer linearity tests.
CEOS Definitions— The Web site for stan-dard definitions was maintained (http://
www.boulder.nist.gov/div8 1 3/stdterms/index.htm)
and Chapters 1 and 2 of the compilation of stan-
dard definitions for microwave radiometry were
accepted by the Committee on Earth Observation
Satellites (CEOS).
Calibrations
In FY 2004, calibrated 8 devices for custom-ers.
Collaborations
Warsaw University ofTechnology (W. Wiatr),
on-wafer noise-parameter measurements
IBM and RFMicroDevices (Kelvin Project),noise parameters of ULSI devices
National Polar-orbiting Operational Environ-
mental Satellite System (NPOESS), ATMS Cali-bration and Validation Working Group
NOAA Environmental Technology Laboratory(A. Gasiewski and M. Klein), calibration target
characterization
12 Electronics and Electrical Engineering Laboratory
NASA Microwave Instrument TechnologyBranch (P. Racette, J. Piepmeier), calibration tar-
get characterization
Physics Laboratory (J. Rice, C. Johnson), ra-
diometer calibration and validation and target char-
acterization
Information Technology Laboratory (K.
Coakley, J. Splett), nonlinear modeling of tunnel
diode detectors
Standards and TechnicalCommittee Participation
Consultative Committee on Electricity and
Magnetism (CCEM), Working Group on RadioFrequencies, Chairman
IEEE Microwave Theory and Techniques So-
ciety, Technical Committee on Microwave Low-
Noise Techniques, TC-14
IEEE Geoscience and Remote Sensing Soci-
ety Technical Committee on Instrumentation and
Future Technologies
IEEE Geoscience and Remote Sensing Soci-
ety liaison to IEEE Standards Board
CEOS Working Group on Calibration and Vali-dation, Microwave Sensors Subgroup, Standard
Terminology compilation (Chapters I and II)
Recent Publications
J. Randa. D. K. Walker, A. E. Cox, and R. L. Billinger, “Errors
Resulting from the Reflectivity of Calibration Targets,” IEEE.
Trans. Geosci. Remote Sensing, in press.
J. Randa, A. E. Cox, D. K. Walker, M. Francis, J. Guerrieri,
and K. MacReynolds, “Standard Radiometers and Targets for
Microwave Remote Sensing," Int. Geoscience and Remote
Sensing Symp. ( IGARSS), Anchorage, AK, paper 2TU_30_1
0
(September 2004).
D. K. Walker, K. J. Coakley, and J. D. Splett, “Nonlinear Mod-
eling ofTunnel Diode Detectors,” Int. Geoscience and Remote
Sensing Symp. ( 1GARSS), Anchorage, AK, paper 8ITH_14_1
1
(September 2004).
J. Randa, D. K. Walker, A. E. Cox, and R. L. Billinger, “Errors
Due to the Reflectivity of Calibration Targets,” Int. Geoscienceand Remote Sensing Symp. (IGARSS), Anchorage, AK. paper
4TH_70_02 (September 2004).
J. Randa, D. K. Walker, M. Francis, and K. MacReynolds,
“Linking Microwave Remote-Sensing Measurements to Fun-
damental Noise Standards,” Conf. Precision Electromagn.
Meas., London, U.K., pp. 465-466 (June 2004).
G. Free, J. Randa, and R. L. Billinger, “Radiometric Measure-
ments of a Near-Ambient, Variable-Temperature Noise Stan-
dard,” Conf. Precision Electromagnetic Meas., London, U.K.,
pp. 414-415 (June 2004).
W. Wiatr and D. K. Walker, “Systematic Errors in Noise Pa-
rameter Determination Due to Imperfect Source Impedance
Measurement,” Conf. Precision Electromagnetic Meas., Lon-
don, U.K., pp. 416-417 (June 2004).
J. Randa and D. K. Walker, “Amplifier Noise-Parameter Mea-
surement Checks and Verification,” 63rd ARFTG Conf., FortWorth, TX, pp. 41-45 (June 2004).
J. Randa, “Traceability for Microwave Remote-Sensing Radi-
ometryf'NIST Interagency Report, NIST1R 6631 (June 2004).
Electromagnetics Division 13
New Directions in Microwave ElectronicsNonlinear Device Characterization
Technical Contacts:
Don DeGrootJeffrey Jargon
Staff-Years (FY 2004):
2 professionals
1 research associate
“Your work represents
an important develop-
ment in this area,
opening a new applica-
tion ofANNs to measure-
ment standards. ”
Prof. Zhang. Nortel/NSERC
Industrial Chair in CAECarleton University
January 2002
Goals
This project develops new and general measure-
ment methods for characterizing nonlinear micro-
wave and millimeter-wave circuits, semiconductor
devices, and advance technology elements. It re-
fines and transfers these methods to research and
development laboratories through international
collaborations.
Jeffrey Jargon measures a commercial harmonic
phase reference standard using the large-signal
network analyzer.
Customer Needs
Radio-frequency (RF) measurements from tens of
megahertz to hundreds of gigahertz are used ex-
tensively throughout the development and deploy-
ment of advanced technology. Historically the fo-
cus was on linear network characterization, but
more recently the commercial wireless industry
identified the need for new methods in nonlinear
network analysis and requested NIST’s assistance.
Additionally, a growing effort in advanced bio- and
nano-technologies is now calling for related non-linear system identification tools.
The needs in nonlinear RF network analyzers aretwo-fold. Engineers and researchers require accu-
rate measurements of the absolute wave variables
of periodic, harmonically rich signals, not just the
wave-variable ratios at single frequencies that are
used in linear network analysis. Second, they need
efficient methods of capturing the observed wave
variables over an adequate range of states in order
to model the behavior of their nonlinear networks.
We formed the Nonlinear Device Characterization
(NDC) Project in FY97 to address these specificneeds, working first with the commercial wireless
world.
Technical Strategy
The main strategy ofthe NDC Project is to developaccurate measurements of broadband wave-vari-
ables (up to 50 gigahertz at this point, with plans to
expand). With solid measurement techniques and
statements ofmeasurement uncertainty we can pur-
sue our secondary strategies ofnew measurement-
based modeling and canonical nonlinear devices
for measurement verification. While we often dem-
onstrate the application of new methods in indus-
trial problems, our strong physical foundation natu-
rally leads to methods and tools that are general
and support a wide range of advanced technology.
The NDC Project established a new and uniquemeasurement facility by acquiring a passive
intermodulation (PIM) analyzer and prototype
large-signal network analyzer (LSNA). The facil-
ity provides a unique collection of equipment and
methods in open U.S. research laboratories, and
the most general approach to measuring large-sig-
nal responses in nonlinear RF networks. We aredeveloping accurate calibration and measurement
techniques for users ofLSNA-like equipment, and
recently collaborated with the Vrije Universiteit
Brussel on new statistical approaches for vector
network analyzer identification and correction. Weare also developing a nonlinear superconducting
device for the verification ofwave-variable phase,
and have developed a diode circuit-verification
wafer for an interlaboratory measurement compari-
son.
One way the NDC Project is supporting high-fre-quency radio design is in measurement-based mod-
eling, that is, linking the accuracy of a model to the
quality measurements. Industrial experts estimate
that the “basic” RF power amplifier accounts forover 50 percent of base station costs and over 20
percent of the total wireless link cost, due to high
development costs. These amplifier circuits are
supposed to be linear, but this is often an unrealis-
tic specification in commercial applications, where
cost and battery drain margins are small. More ac-
curate nonlinear device and amplifier models would
reduce radio transceiver costs dramatically. Like-
wise, the cost of microwave transistor mixer cir-
14 Electronics and Electrical Engineering Laboratory
cuits could be reduced. Through various collabo-
rations, the NDC team has developed artificial neu-ral-network models for power amplifiers, and ex-
tracted mixer transfer admittance models, both from
LSNA measurements. Additional contributions inthis area will significantly improve design-cycle
efficiency and trade between manufacturers.
The NDC team is now working on methods thatwill bring wave-variable measurements to nano-
technology development. An emerging project strat-egy is to focus on connection methods and new cal-
ibration frameworks to extend our expertise in
broadband wave-variable measurements to the elec-
trical characterization of nanostructures.
Next year we will develop behavioral modelingmethods for power amplifiers using large-signal net-
work analyzer data. We will formulate large-signalscattering parameter descriptions ofnonlinear cir-
cuits under specific stimuli. We will develop sto-chastic methods of vector network analyzer identi-
fication and correction. We will do an uncertaintyanalysis ofLSNA wave-variable measurements. Wewill participate in an interlaboratory measurement
comparison for LSNAs and LSNA-like equipment.
Accomplishments
Improved Calibration of Large-Signal and
Traditional RF Vector Network Analyzers Us-ing New Maximum Likelihood Estimator— Incollaboration with the Vrije Universiteit Brussel, a
statistical method was developed for identifying
vector network analyzer parameters, and the un-
certainty in the parameters. This is a new frame-
work to LSNA and VNA measurement correction,and deviates significantly from traditional deter-
ministic methods used in the industry.
Discovered Warm-Up Drift in HarmonicPhase Reference Standards Used in Commer-cial Large-Signal Network Analyzers— In col-laboration with Information Technology Labora-
tory an empirical model was developed for the
warm-up drift in harmonic phase standards used to
calibrate the phase distortion of nonlinear vector
network analyzers. Using this model, we prescribeda stability point. This contribution significantly
improves LSNA phase distortion calibrations, andis already being adopted by LSNA users.
Completed Development of Relationships
between Nonlinear Large-Signal Scattering Pa-
rameters and Nonlinear Large-Signal Imped-
ance Parameters — We provided the industrialcommunity with important new figures of merit for
nonlinear microwave circuit analysis that can be
readily employed as computer-aided tools for wire-
less component design or in measurement compari-
son experiments.
Demonstrated Nonlinear Superconductor
Device as Potential Phase Reference— A high-temperature superconducting device with a calcu-
lable nonlinear response was developed. Measured
third-order response on LSNA and showed its phasematch prediction. This device is potentially the first
true, independent standard in verifying LSNA phasecalibrations.
Collaborations
Vrije Universiteit Brussel, Department ELEC,
Statistical LSNA identification and correction tech-niques.
University of Florence, Electrical and Com-puter Engineering Department, Measurement-based
behavioral models of microwave mixer circuits.
Information Technology Laboratory, Harmonic
Phase Reference repeatability and drift analysis;
Wave-variable and scattering parameter statistics;
Interlaboratory measurement comparison data
analysis.
University of Colorado, Boulder, Artificial
Neural Network modeling of nonlinear amplifier
circuits and VNA calibration standards.
Awards
Department of Commerce Silver Medal for
NDC Project, 2003
Automatic RF Techniques Group (ARFTG)Conference Best Poster Paper
Professional Committee
Participation
Jeff Jargon serves as Chair of the IEEE MTT-STechnical Committee on Microwave Measurements
Jeff Jargon serves as Chair of the IEEE MTT-S
Standards Coordinating Committee
Recent Publications
J. A. Jargon, J. D. Splett, D. F. Vecchia, and D. C. DeGroot,
"Modeling Warm-Up Drift in Commercial Harmonic Phase
Standards,” Conf. Precision Electromagn. Meas., pp. 612-613
(July 2004).
J. A. Jargon, K. C. Gupta, and D. C. DeGroot, “Nonlinear Large-
Signal Scattering Parameters: Theory and Application,” 63rd
ARFTG Conf., pp. 157-174 (June 2004).
Electromagnetics Division
“Thank you for the paper
[Multiline TRL Revealed].
Comprehensive and
useful!”
Marek Schmidt
Philips Semiconductor
April 2003
D. C. DeGroot, Y. Rolain, R. Pintelon, and J. Schoukens, “Cor-
rections for Nonlinear Vector Network Analyzer Measurements
Using a Stochastic Multi-Line/Reflect Method,” IEEE MTT-SInt. Microwave Symp., pp. 1735-1738 (June 2004).
J. Jargon, K. C. Gupta, A. Cidronali, and D. DeGroot, “Ex-
panding Definitions of Gain by Taking Harmonic Content into
Account,” Int. J. RF Microwave Computer-AidedEng. 13 , 357-369 (September 2003).
J. A. Jargon. D. C. DeGroot, and D. F. Vecchia, “Repeatability
Study of Commercial Harmonic Phase Standards Measured
by a Nonlinear Vector Network Analyzer,” 62nd ARFTG Conf,pp. 243-258 (December 2003) (best poster paper award).
A. Cidronali, G. Loglio, J. A. Jargon. K. A. Remley, I. Magrini,
D. C. DeGroot, D. Schreurs, K. C. Gupta, and G. Manes, "RF
and IF Mixer Optimum Matching Impedances Extracted by
Large-Signal Vectorial Measurements,” Proc. European Gal-
lium Arsenide and Other Compound Semiconductor Applica-tion Symp, (October 2003).
J. C. Booth, K. Leong, S. A. Schima, J. A. Jargon, and D. C.
DeGroot, “Design and Characterization of a Superconducting
Nonlinear Reference Device,” 62nd ARFTG Conf., pp. 61-70(December 2003).
D. Schreurs, J. A. Jargon, K. A. Remley, D. C. DeGroot, and K.
C. Gupta, "Artificial Neural Network Model for HEMTs Con-structed from Large-Signal Time-Domain Measurements,” 59th
ARFTG Conf., pp. 31-36 (June 2002).
D. C. DeGroot, J. A. Jargon, and R. B. Marks, “Multiline TRLRevealed,” 60th ARFTG Conf., pp. 131-155 (December 2002).
J. A. Jargon, K. C. Gupta, and D. C. DeGroot, “Applications of
Artificial Neural Networks to RF and Microwave Measure-ments,” Int. J. RF Microwave Computer-Aided Eng. 12 , 3-24(January 2002).
16 Electronics and Electrical Engineering Laboratory
New Directions in Microwave Electronics:Metrology for Wireless Systems
Goals
The Metrology for Wireless Systems project de-
velops improved measurement methods for both
well-established and newly emerging wireless com-
munication systems in response to pressing needs
of U.S. industry' and the public safety sector. This
goal is achieved by use of advanced measurement
technology to ( 1 ) develop new and improved cali-
brations for existing instrumentation, (2) accurately
represent the effects ofnonlinear elements such as
power amplifiers on system performance, and (3)
implement cost-effective methods for reliable ra-
dio communications for the public safety sector.
LJjf v— v- -2-12 jT
Uf" rr & 1 1 1
: 'j (
I ijf ' - c c c c
Instrumentation that aids in the refinement and
development ofmetrologyfor wireless communication
systems.
Customer Needs
Wireless communication systems take many shapes
and forms, including cellular technology for voice,
image, and video transmission, high-speed local-
area and ad-hoc data networks, and RFID tags forapplications such as toll payment and inventory
control. The first responder community utilizes
wireless telecommunications extensively in emer-
gency scenarios, as well as for broadband data trans-
mission for maps, photos, and other images. Accu-
rate system characterization is essential in all of
these applications because it increases efficiency
of system design and validates overall system per-
formance. For the commercial sector, this leads to
increased productivity and revenue. For the public
safety sector, accurate system characterization can
mean the difference between life and death in emer-
gency situations.
Technical Strategy
Technical Contact:
Kate Remley
Staff-Years (FY 2004):
2 professionals
3 research associates
The commercial wireless market and the first re-
sponder community have similar yet distinct needs.
As a result, this project is divided into two main
thrusts: Measurements for Wireless Systems and
Improved Communications for First Responders.
Measurements for Wireless Systems — Thisproject was newly formed in FY 2004, having origi-nated in the Nonlinear Device Characterization
project in FY 2000. The project takes advantage ofnew measurement instrumentation capable of ac-curately characterizing systems that have nonlin-
ear elements to develop new and refined calibra-
tion and measurement methods appropriate for
next-generation and broadband wireless system
technologies. Using this instrumentation we are ableto evaluate measurements made on equipment com-
monly utilized in the industry.
“Wireless applications
have quickly grown to
become an important
driver for semiconductor
products and technolo-
gies.”
The International Technology
Roadmap for Semiconductors:Executive Summary (2003)
Our goals include development of impedance mis-
match correction techniques for vector signal gen-
erators in their large-signal operating state, devel-
opment and characterization of test and calibration
signals useful to the wireless industry, and assess-
ment of the effect of standard test equipment
nonidealities on system characterization.
Improved Wireless Communications for First
Responders — Until now, first responders havehad little guidance in predicting how well their sys-
tems will operate in a variety of difficult transmis-
sion scenarios. We are developing test methods tocharacterize signal degradation, including attenu-
ation and phase distortion, in complex environments
including large buildings and basements.
In particular, we are focusing on development of
wideband measurement methods in the new 4.9 gi-
gahertz public safety radio band for transmission
of voice, data, images, and video. The project is
also involved in compilation ofan array of straight-
forward, inexpensive, retrofitable techniques to be
used in emergency weak-signal scenarios, such as
tunnels, basements, and collapsed buildings.
Electromagnetics Division 17
“Inadequate and unreli-
able wireless communi-
cations have been
issues plaguing public
safety organizations for
decades. In many cases,
agencies cannot perform
their mission-critical
duties”
“Statement of Requirements:
Background on Public Safety
Wireless Communications,”
The SAFECOM Program,Department of HomelandSecurity, v. 1.0
(March 10, 2004)
Project staffand othersfrom the Electromagnetics
Division carry out propagation measurements (using
the mobile cart behind the staff) and investigate
methodsfor weak-signal detection at a large public
building scheduledfor implosion in New Orleans.
Accomplishments
Mathematical Description of Third-Order
Intermodulation Products — We developed astraightforward, device-independent mathematical
description of third-order intermodulation distor-
tion in amplifier circuits based on two-tone analy-
sis. We verified the description with measurementson the large-signal network analyzer (LSNA). The
measurements included a technique that extends the
modulation bandwidth ofthe LSNA. Accurate char-
acterization of intermodulation is a key step in the
field of pre-distortion correction, where the non-
linear behavior of a system is measured in real time
and the incoming signal is distorted to compensate
for the system’s nonlinearity.
Method to Measure the Small-Signal Re-flection Coefficient ofVector Signal Generators
under Large-Signal Operating Conditions —This technique consists of a one-port measurement
performed at the output port of a vector signal gen-
erator while it is in its large-signal operating state.
The method captures both the standard and the
phase-conjugated mixing behavior associated with
nonlinear devices. This new method uses the unique
capabilities of the LSNA to overcome limitationson VNA measurements ofreflection coefficient, andwill enable mismatch correction ofsources in their
operating state, including their phase-conjugated
behavior, for the first time.
Comparative Measurements of Multisine
Test and Calibration Signals — This collabora-tion involves measurements of identical multisine
signals with instrumentation capable of character-
izing nonlinear systems, including an LSNA, a vec-
tor signal analyzer, a calibrated sampling oscillo-
scope (with the Optoelectronics Division) and the
NIST Sampling Waveform Analyzer (with theQuantum Electrical Metrology Division). Some ofthese instruments may enable development ofnewtypes of multisine calibration signals, since they
either now have or will soon have uncertainty analy-ses associated with their measurements.
Calibration of a Receiver-Based Measure-
ment System for Weak-Signal Detection — Wedeveloped a method to measure absolute electric
field strength using a communications receiver-
based system. This method will enable measure-
ment ofvery weak signals from public safety trans-
ceivers in terms of absolute field strength. We havealready applied the method in a collaborative ef-
fort with the Phoenix Fire Department, which has
conducted extensive signal testing of their radio
systems in large public buildings in the Phoenix
area.
Measurement Methods for Public Safety in
the 4.9 Gigahertz Frequency Band— We devel-oped a normalization technique that facilitates cal-
culation of a common digital system figure ofmeritcalled error vector magnitude (EVM). We devel-oped a multisine test signal to emulate the broad-
band digital signal used in common transmissionschemes. Public safety organizations hope to take
advantage of such existing wideband transmission
protocols shifted in frequency to the 4.9 gigahertz
band. This work aims to provide them with a simple
test protocol for their broadband channels.
Investigation of Metallic Debris as Ad HocAntenna Arrays— We carried out measurementsusing building materials such as conduit, pipe, and
rebar as radiating structures to investigate whether
they can enhance signal transmission and recep-
tion from deep within a building. Using metallic
debris as an ad hoc radiator in a damaged or col-
lapsed building may provide a new type of life-
saving tool in emergency scenarios where commu-
nication is made difficult by large amounts of de-
bris.
Collaborations
Agilent Technologies, K.U. Leuven: device-
independent mathematical description of third-or-
der intermodulation in weakly nonlinear systems
K.U. Leuven: method to extend measurement
bandwidth ofLSNA for intermodulation distortionmeasurements
Georgia Tech: normalization to facilitate cal-
culation oferror vector magnitude (EVM ) in broad-band wireless systems
18 Electronics and Electrical Engineering Laboratory
K. U. Leuven and Georgia Tech: development
of multisine signals to emulate broadband digital
modulation
Colorado School of Mines: measurement of
active mixers
Optoelectronics Division and Information
Technology Laboratory: measurement application
ofjitter correction technique
Optoelectronics Division and Quantum Elec-
trical Metrology Division: measurement compari-
son of multisine signals from instrumentation with
measurement uncertainty analyses
Phoenix Fire Department: measurements of
signal strength during field experiments on signal
quality in large public buildings
Awards
Department of Commerce Silver Medal forNonlinear Device Characterization Project Partici-
pation, 2003
ARFTG Conference Best Paper Award, 2003
Professional CommitteeParticipation
IEEE International Microwave Symposium
Technical Program Subcommittee 7 on Nonlinear
Circuit Analysis and System Simulation
Automatic RF Techniques Group (ARFTG)Nonlinear Vector Network Analyzer Users’ Forum,
coordinator
Recent Publications
K. A. Remley, D. F. Williams, D. Schreurs, and J. Wood, “Sim-
plifying and Interpreting Two-Tone Measurements,” IEEETram. Microwave Theory Tech., in press.
J. Verspecht, D. F. Williams, D. Schreurs, K. A. Remley, and
M. D. McKinley, “Linearization of Large-Signal Scattering
Functions,” IEEE Trans. Microwave Theoiy Tech., in press.
D. F. Williams, F. Ndagijimana, K. A. Remley, J. Dunsmore,
and S. Hubert, “Scattering Parameter Models and Representa-
tions of Microwave Mixers,” IEEE Trans. Microwave TheoryTech., in press.
D. Schreurs, K. A. Remley, W. Van Moer, “NVNA Users’ Fo-rums: Mission and Overview," Proc. 2004 European Micro-
wave Conf., in press.
K. A. Remley, D. Schreurs, D. F. Williams, and J. Wood, "Ex-
tended NVNA Bandwidth for Long-Term Memory Measure-ments,” IEEE MTT-S Int. Microwave Symp., pp. 1739-1742(June 2004).
D. Schreurs, K.A. Remley, and D.F. Williams, “A Metric forAssessing the Degree of Device Nonlinearity and Improving
Experimental Design," IEEE MTT-S Int. Microwave Symp.,
pp. 795-798 (June 2004).
D. Schreurs, K.A. Remley, M. Myslinksi, and R. Vandermissen,
“State-Space Modeling of Slow-Memory Effects based on
Multisine Vector Measurements,” 62nd ARFTG Conf., pp. 81-88 (December 2003).
D. Schreurs, M. Myslinski, and K. A. Remley, “RF Behavioural
Modelling from Multisine Measurements: Influence of Exci-
tation Type,” Proc. 2003 European Microwave Conf., pp. 1011-
1014 (October 2003).
Electromagnetics Division 19
New Directions in Microwave ElectronicsHigh-Speed Microelectronics
Technical Contact:
Dylan Williams
Staff-Years (FY 2004):
1 professional
1 technician
1 research associate
“A major roadblock will
be the need for high
frequency, high pin
count probes and test
sockets; research and
development is urgently
required to enable cost-
effective [test] solutions
with reduced parasitic
impedance. ”
2003 International
Technology Roadmapfor Semiconductors
Goals
This project supports the microwave, telecommu-
nications, computing, and emerging nanoelectron-
ics industries through research and development
of high-frequency on-wafer electrical metrology for
micrometer-scale and nanoscale electrical devic-
es. It is developing electrical metrology in coaxial
transmission lines to 1 1 0 gigahertz and on-wafer
metrology to 400 gigahertz for microwave signal
and signal source characterization, wireless sys-
tems, high-speed microprocessors, and high-speed
nanocircuits and interconnects, and the telecom-
munications industry. The work is interdisciplinary
and relies on strong collaborative efforts with the
Optoelectronics Division.
The NIST electro-optic sampling system provides
traceabilityfor our measurements and calibrations.
Developedjointly with the Optoelectronics Division.
Customer Needs
The rapid advance in the speed ofmodern telecom-
munications and computing systems drives this
project. Characterizing signal integrity in micro-
processors requires at least 10 gigahertz of cali-
brated measurement bandwidth on structures fab-
ricated on a nanoscale. Limited available bandwidth
is pushing wireless systems into the millimeter-
wave region of 30 to 100 gigahertz, where accu-
rate microwave signal and signal source character-
ization is difficult. Optical links operating at 40
gigabits per second require electrical metrology to
1 10 gigahertz. Emerging high-speed digital circuits
with clock rates ofover 100 gigahertz require elec-
trical metrology to 400 gigahertz. These extraordi-
nary advances in technology require new high-
speed coaxial and on-wafer microwave signal and
waveform measurements. Because the speed ofthe
devices is often linked to size, it is important to
develop this high-speed metrology at both conven-
tional IC and nanoscale dimensions and at both
conventional and high impedances.
Technical Strategy
Coaxial connectors pose insurmountable economic
hurdles for high-speed telecommunications and
computing. For example, a single coaxial adapter
that supports frequencies to 110 gigahertz costs
upwards of $1000. This project focuses on the only
feasible alternative: high-speed on-wafer metrol-
ogy. The project’s initial focus on developing me-
trology for on-wafer network analysis for MMICshas been expanded to include metrology for sili-
con ICs and differential interconnects. More re-
cently the project has further expanded the focus
to noninvasive probing on a nanoscale and to ul-
tra-high-speed modulated microwave signal, sig-
nal-source, and waveform characterization.
The project focuses on extending fundamental mi-
crowave and on-wafer metrology to higher frequen-
cies and to modulated signals and waveforms.
Working together with EEEL’s Optoelectronics Di-
vision, we have developed a fully calibrated electro-
optic sampling system for characterizing photode-
tectors and calibrating oscilloscopes for microwave
signal characterization. This has set the foundation
for a number of new developments in microwave
metrology, including: modulated microwave sig-
nal and coaxial signal-source characterization to
1 1 0 gigahertz, verifying the 3-mixer calibration, and
performing electro-optic on-wafer scattering and
waveform measurements beyond 110 gigahertz.
This fundamental metrology tool will be crucial to
bringing a new generation of calibrated high-fre-
quency oscilloscopes, MTAs, and related instru-
ments to the microwave engineer’s workbench.
Whenever possible, we are extending the use of
these instruments directly to the wafer level. Weare not only developing calibration procedures for
today’s high-performance electrical probes, but we
are also laying the foundations for 200 gigahertz
to 400 gigahertz calibrations for tomorrow’s probes.
We are also developing techniques for performingnoninvasive high-impedance on-wafer waveform
measurements for signal-integrity characterization
20 Electronics and Electrical Engineering Laboratory
in digital silicon ICs and other small circuits. This
effort is particularly important for the development
of electrical metrology for nanoscale devices,
which, due to their small sizes, have extremely high
electrical impedances.
Our plan is to electrically characterize an active
high-impedance probe with our existing VNA cali-bration methods. We will then characterize the sameprobe on our 200-gigahertz-bandwidth EOS sys-tem. This will lay the groundwork for very-high-
speed on-wafer calibrations for digital IC and
nanoelectronics. We will develop joint time-do-main/frequency-domain uncertainty analysis for
coaxial photodiode pulse sources. The calibration
and uncertainty representation will include imper-
fections in the electro-optic sampling system and
electrical mismatch corrections, and will be suit-
able for calibrating oscilloscopes with coaxial ports
in either the time or frequency domains to 1 10 gi-
gahertz. We will develop pulse sources with 400gigahertz bandwidth. Based on these sources, de-
velop on-wafer waveform characterization ability
to 400 gigahertz. We will apply high-speed wave-form metrology to microwave problems, including
the characterization of electrical phase standards,
microwave sources, and microwave mixers.
Traceable mismatch-corrected 50 gigahertz micro-
wave oscilloscope calibration with an EOS-character-
ized photodetector.
Accomplishments
High-Impedance Probe Characterization- We developed a frequency-domain method ofcharacterizing high-impedance probes suitable for
performing noninvasive on-wafer waveform and
signal-integrity measurements.
Electro-Optic Sampling System— In a col-laborative effort with the Optoelectronics Division,
we built an on-wafer electro-optic sampling sys-
tem. We have developed calibration methods and
uncertainty analyses in coaxial media to 1 1 0 giga-
hertz and on-wafer to 200 gigahertz.
On-Wafer Measurement and Characteris-
tic Impedance— We developed accurate multilineTRL on-wafer calibrations, on-wafer calibrationverification methods, and compact calibration al-
ternatives with verified accuracy. We developed anaccurate method ofmeasuring the characteristic im-
pedance of a transmission line fabricated on lossy
silicon substrates and an accurate on-wafer cali-
bration using this method.
Multiport and Coupled-Line Characteriza-
tion — We developed instrumentation and meth-ods for accurately and completely characterizing
multiports and small printed coupled lines.
Thin-Film Characterization — In collabo-ration with our Microwave Materials Group, wecharacterized low -k dielectrics fabricated at
SEMATECH using transmission-line methods de-veloped at NIST.
Software
Time-Base-Correction Software for jitter and
time-base-distortion correction of oscilloscope
measurements.
StatistiCAL measurement software implement-
ing general on-wafer and coaxial calibrations with
orthogonal distance regression and uncertainty es-
timation.
MultiCal measurement software implementing
the multiline TRL calibration.
Four-port measurement software for perform-
ing orthogonal two-port, three-port, and four-port
measurement with in-line calibrations and inexpen-
sive hardware.
Software for characteristic impedance of sili-
con transmission lines designed to accurately de-
termine the characteristic impedance of transmis-
sion lines fabricated on silicon substrates.
CausalCat Software: For computing causal
characteristic-impedance magnitude from the phase
ofthe integral ofthe Poynting vector over the guide
cross section.
Recent Publications
D. F. Williams, P. D. Hale, T. S. Clement, and J. M. Morgan,
“Calibrated 200 GHz Waveform Measurement,” IEEE Trans.
Microwave Theory Tech., in press.
J. Verspecht, D. F. Williams, D. Schreurs, K. A. Remley, and
M. D. McKinley, “Linearization of Large-Signal Scattering
Functions,” IEEE Trans. Microwave Theory Tech., in press.
Electromagnetics Division 21
D. F. Williams, F. Ndagijimana, K. A. Remley, J. Dunsmore,
and S. Hubert, “Scattering-Parameter Models and Representa-
tions for Microwave Mixers,” IEEE Trans. Microwave Theory
Tech., in press.
P. Kabos, H. C. Reader, U. Arz, and D. F. Williams, “Cali-
brated Waveform Measurement with High-Impedance Probes,”
IEEE Trans. Microwave Theory Tech. 51 , 530-535 (February
2003).
D. F. Williams, C. M. Wang, and U. Arz, “An Optimal Multiline
TRL Calibration Algorithm,” Int. Microwave Symp., pp. 1819-1822 (June 2003).
K. A. Remley, D. F. Williams, D. Schreurs, G Loglio, and A.Cidronali, “Phase Detrending for Measured Multisine Signals,”
61st ARFTG Microwave Measurement Conf., pp. 73-83 (June2003) (ARFTG best paper award).
K. A. Remley and D. F. Williams, “Sampling Oscilloscope
Models and Calibrations,” Int. Microwave Symp. (invited), pp.1507-1510 (June 2003).
A. Louh, U. Arz, H. Grabinski, D. F. Williams. D. K. Walker,
and A. Weisshaar, “Broadband Impedance Parameters ofAsym-
metric Coupled CMOS Interconnects: New Closed-Form Ex-pressions and Comparison with Measurements,” 7th IEEE
Workshop on Signal Propagation on Interconnects, Siena, Italy
(May 2003).
U. Arz, P. Kabos, and D. F. Williams, “Measuring the Inva-
siveness of High-Impedance Probes,” 7th IEEE Workshop on
Signal Propagation on Interconnects, Siena, Italy (May 2003).
P. D. Hale and D. F. Williams, “Calibrated Measurement of
Optoelectronic Frequency Response,” IEEE Trans. MicrowaveTheory Tech. 51
,1422-1429 (April 2003) (EEEL 2003 Out-
standing Authorship Award).
Electronics and Electrical Engineering Laboratory22
New Directions in Microwave Electronics:Radio-Frequency Nanoelectronics
Goals
This project develops fundamental metrology, in-
strumentation techniques, and theory needed for the
microwave, telecommunications, magnetic record-
ing, and computing industries. Research is focused
on standards and tools for visualization and char-
acterization of materials and devices at the
nanoscale. Emphasis is on waveform and fre-
quency-domain metrology of nanoscale intercon-
nects and packaging, and on microscopy and im-
aging of devices and materials.
Customer Needs
The National Nanotechnology Initiative calls for
the creation of a new research and development
infrastructure to tackle the challenges and oppor-
tunities ofnanotechnology. Full exploitation of the
potential ofnanotechnology requires long-term in-
terdisciplinary research across such fields as chem-
istry, physics, materials science, electronics, bio-
technology, medicine, and engineering. Research
will be conducted to provide fundamental measure-
ments needed for future generations of hardware
needed to replace semiconductor and magnetic
technology in a decade or so. Our expertise in mi-
crowave metrology, optics, materials characteriza-
tion, clean room microfabrication — as well ascollaboration with other projects — helps us de-velop new tools and materials characterization tech-
niques for nanotechnology in the frequency range
up to 1 00 gigahertz and beyond.
Technical Strategy
Based on an understanding of the physics of the
interaction between materials and electromagnetic
waves, we are focusing on the development ofnewexperimental tools and techniques that address fu-
ture needs of industry that require noninvasive prob-
ing and characterization of submicrometer and
nanoscale structures at radio frequencies (RF). Weare working with the Magnetics Group, the Opto-
electronics Division, and the Materials Science and
Engineering Laboratory to apply on-wafer measure-
ment methods to nanoscale devices and intercon-
nects such as carbon nanotubes or Si nanowires.
We are developing techniques for performingnoninvasive on-wafer waveform measurements for
signal-integrity characterization in digital silicon
integrated circuits and in magnetic recording me-
dia, and calibration procedures for nanoscale elec-
trical and magnetic probing systems. In order to
characterize nanostructures, it is important to ex-
tend the high spatial and temporal resolution of
existing nanoprobes. The objective is to observe
and control the dynamical evolution of physical
phenomena in nanostructures. The development of
nanometer-scale RF pump-probe techniques, na-nometer-scale feedback and control, and other
probes of local behavior are sought to provide new
insight into nanoscale phenomena.
Radio-Frequency Atomic-Force Microscope
(RF-AFM) Development— Several projects re-quire high-frequency, near-field imaging capabili-
ties. We are developing experimental techniquesin collaboration with the Magnetics Group and the
Materials Science and Engineering Laboratory for
measuring the high-frequency response and noise
of small magnetic structures. The focus is on the
contribution of the edges on the measured charac-
teristics of small samples. The results from differ-
ent experimental techniques will be compared and
evaluated to get a better understanding of the be-
havior of small magnetic elements.
The possibility of chip-to-chip wireless communi-
cation requires the design of novel micrometer-
scale antennas with special radiation patterns to
ensure the errorless transfer of data from chip to
chip at high data-transfer rates. The imaging of the
near-field radiation patterns of such structures is
of crucial importance for such application